Die-stock.



R. B. TEWKSBURY.

DIE STOCK.

APPLICATION FILED MAY 4, 1912.

1 04 1 Q8 Patented Dec. 24, 1912.

0 v COLUMBIA PLANOORA PH c0" WASHINGTON. 0. c4

RUSSELL B, TEWKSBUBY, 0F QLEVELANQQHIO.

DIE-STOCK.

Specification of Letters Patent.

' Patented Dec. 24, 1912.

ppli a o fi d y 159. Senia Q- .95.2

To all whom. it may concern:

Be it known that I, RUSSELL B. Tnw xs- BURY, a citizen of the UnitedStates, residlng at Cleveland, in the county of Guyahoga and StateiofOhio, have invented a certain new and useful Improvement in Die-Stocks,of which the following is a full, clear, and exact description.

This invention relates to improvements 111 the kind of die stocks whichhave a capacity for adjustment such as will adapt them for threadingwork of different diameters. I The object of the invention is toprovidesuch a die stock with means which, regardless of the size towhich the tool is set, will automatically withdraw the diesifrom thework after the desired length of thread has been cut, and will hold themin the withdrawn position while the work holder and di'e carthread, andwill cause the dies. tobe re turned to their working positions when thedie carrier and work holder. have'reached the above mentioned startingposition. v The invention consists n the constructlon and combination ofparts hereinafter de scribed and pointed out definitely in the claims. i

. In the drawing, Figure 1 is a front end view of a die stock embodyingthe invention. Fig. 2 is a side elevation with one side of the die stockin central section Fig. 3 is a longitudinal section at right angles tothe plane at which the sectional part of Fig. 2 is taken. Fig. 4 is aninside view of a part of the templet bar showing the rear ends of theguide grooves 6 and 6 Referring to the parts by letters, 1 representsthe work holder which is of familiar construction, being a built upmember of tubular form, so that the pipe or other cylindrical piece ofwork to be threaded may be passed through it, and being provided withsuitable means whereby it may be clamped to said work. The die carrier 2is likewise tubularand'is capable of moving threaded so that it mayscrew'into the inter-.

nally threaded work holder, wherefore', as

the ,die carrier is turned relatively to the work holder, it will movelongitudinally rel? ative thereto at such a rate as isdetermined thesetwo parts.

Near the front endof radially movable guideways 2" in which the radiallymovable dies or chasers 3 are movablymounted. A cam plate 4" isrotatably mountedupon the cylindrical front end of the die carrier, andis held thereon by the cap 7. The cam plate 4 has on its rear faceeccentric scrolls 4 which engage the dies, so

by the pitch'of the engaging threads upon the die carrier are that, asthe cam plate is turned upon the die carrier, all of the dies are movedSIIHUItHIIQr Thedie stock, to the extent end rof the other part l ofsaid work holder.

This ring is compelled to turn with the die carrier by means of two pins8, fixed to the mug, and extending longitudinally forward therefromthrough holes in the handle sockets '2 of the die carrier,.the pinsbeing freely movable in said holes. y

,6 represents the templet bar which is fixed to the ring 5 and projectsforward therefrom'alongside of-the die carrier. The

inner face of this templet bar is provided with an endless guide forcontrolling the position of the cam plate 5. This guide,as shown, isagroove having two branches 6 and 6 which extend in a general forwardand backward direction and which arejoined together at their front andrear ends. A lug 5P projects out from the cam plate into said groove.The branch 6 is inclined as shown, at such an angleto the axis of thetool that, as the lug d travels rearward in said groove while the diesare cutting the thread on the work, the cam plate will be turned enoughto'cause the required recession of the dies to impart the desired taperto thethread which is being, out.

enough, the dies, due to the outthrust of the work, will move in thereceding direction nd caus the cam plate t e respo control such movementwhilethe threadis If the y eccentricity of the cam scrolls 4 is greatbeing cut. If, however, the construction be such that the outthrust ofthe work upon the dies will be insufhcient to move the cam plate, theengagement of said lug with the other inclined wall of the groove 5 willcompel the required movement of the cam plate to produce the requiredrecession of the dies.

\Vhen the thread on a piece of work has been completed, the die carrierwill have been screwed substantially as far as it can go into the workholder, and the lug P will be well behind the angular rear end of theprojection 6 which lies between the two branches 6 and 6 Now, when thedie carrier is unscrewed from the work holder, there will be for thetime being no force at work tending to turn the cam plate in thedirection which would cause the dies to move inward. Therefore the camplate will either remain immovable or will turn in the die recedingdirection. In either event, the lug P will be drawn forward in theguideway and will enter the branch 6 thereof. Preferably the front faceof the lug 4 will be inclined, as shown, so that if a part of it startsto enter the groove 6 the cam plate will be turned in the die recedingdirection by the engagement of the inclined front face of the lug i withthe rear end of the partition 4 so that said lug will'certainly enterthe groove 6 It will travel forward in this groove and will be guidedthereby. The front end of the groove 6 being curved toward and beingconnected with the front end of the groove 6, the lug will be guidedinto the groove 6*, and the cam plate will at the same time be turned soas to set the dies in approximately the correct position to start thecutting of a thread, If, now, the die carrier be screwed into the workholder one turn, or thereabout, before the dies are caused to engage thework, part of the lug at will pass the front end of the partition 6 andthereby, so far enter the groove 6 that it must travel therein when thedie carrier is screwed into the work holder.

In the particular construction shown the adjustability of the die stockto adapt it for cutting threads on work of different diameters isattained by the construction which permits the templet bar 6 to beadjusted circumferentially upon the ring 5. To permit this, said ringhas alateral projection 5 in which is an arcual slot 5. The lower end ofthe templet bar enters this slot and is correspondingly shaped so as toprevent it from turning therein; and said templet bar has a rearwardlyprojecting threaded stem 6 which passes through the slot. By screwing anut 9 onto this stem against the rear face of the ring, the templet barwill be rigidly fixed to the ring at any desired posi tion relativethereto. It will, of course, be

understood that as the templet bar is moved circumferentially upon thering, the cam plate must move to a like extent in the same direction,and this affords the means for adjusting the tool for differentdiameters of work. This particular means for securing this adjustment isnot, however, essential to the invention. In fact, the same result couldbe obtained if the templet bar were not adjustable upon the ring,provided the lug thereof rearward until it unites with the endless guidegroove 6, 6 It is through this open ended groove 6 that the pin 49 onthe cam plate may be introduced into or withdrawn from said endlessguideway, when, for example, it is desired to change the dies.

Having described my invention, I claim 1. In a die stock, thecombination of a tubular work holder adapted to be clamped upon thework, a tubular die carrier which is rotatably and longitudinallymovable relatively to the work holder, radially movable dies mountedupon the die carrier, a cam plate rotatably mounted upon the die carrierand engaging with the dies to control their position, a ring which isrotatable upon the work holder in unison with the die carrier but has nolongitudinal movement relative to the work holder, a templet bar fixedto said ring and extending therefrom longitudinally forward, whichtemplet bar has on its inner face an endless guideway having twobranches which extend in a general forward and backward direction andare connected at their front and rear ends, and a lug which projectslaterally from the cam plate and engages with said guideway.

2. In a die stock, the combination of a tubular work holder adapted tobe clamped upon the work, a tubular die carrier which is rotatably andlongitudinally movable relatively to the work holder, radially movabledies mounted upon the die carrier, a cam plate rotatably mounted uponthe die carrier and engaging with the dies to control their position, aring which is rotatable upon the work holder in unison with the diecarrier but has no longitudinal movement relative to the work holder, atemplet bar fixed to said ring and extending therefrom longitudinallyforward, which templet bar has on its inner face an endless guide groovehaving two branches which extend in a general forward and backwarddirection and are connected at their front and rear ends,

and a lug which projects out from said cam into said guideway, and has abeveled frontace.

3. In a die stock, the combination of a tubular work holder adapted tobe clamped upon the work, a tubular die carrier which is rotatably andlongitudinally'movable relatively to the work holder, radially movabledies mounted upon the die carrier, a cam plate rotatably mounted uponthe die carrier and engaging with the dies to control their position, aring which is rotatable upon the work holder in unison with the diecarrier but has no longitudinal movement relative to the work holder, atemplet bar fixed to said ring and extending therefrom longitudinallyforward, which templet bar has on its inner face an endless guidewayhaving two branches which extendin a general forward and backwarddirection and are connected at their front and rear ends, a lug whichprojects laterally from the cam plate and engages with said guideway,and means whereby the cam plate may be turned independently of anymovement of the die carrier and work holder for the purpose of adjustingthe dies for work of different diameters, and without withdrawing thelug on the cam plate from its engagement with said guideway.

4:. In a die stock, the combination of a tubular work holder adapted tobe clamped upon the work, a tubular die carrier which is rotatably andlongitudinally movable relatively to the work holder, radially movabledies mounted upon the die carrier, a cam plate rotatably mounted uponthe die carrier and engaging wit-h the dies to control their position, aring which is rotatable upon the work holder in unison with the diecarrier but has no longitudinal movement relative to the work holder, atemplet bar which is adjustable circumferentially on the ring andextends therefrom longitudinally for-' ward, which templet bar has onits inner face an endless guideway having two branches which extend in ageneral forward and backward direction and are connected I at theirfront and rear ends, and a lug which Copies of this patent may beobtained for 5. In a die stock, the combination of a tubular work holderadapted to be clamped the work holder, a templet bar fixed to said ringand extending therefrom longitudinally forward, which templet bar has onits inner face two approximately parallel guideway branches which extendin a general forward and backward direction, a lug which extendslaterally from said cam plate into engagement with one of saidguidewaybranches, said guideway branches being connected at one end atleast whereby the lug may pass from one guideway branch into'the other.

6. In a die stock, the combination of a tubular'work holder adapted tobe clamped upon thework, a tubular die carrier which is rotatably andlongitudinally movable relative to the work holder, radially movabledies mounted upon the die carrier, a cam rotatably mounted upon the diecarrier and engaging the dies to control their position,

a rlng which is rotatable upon the work" holder but has no longitudinalmovement v relative to the work holder, a templet bar fixed to said ringand extending therefrom longitudinally forward, which templet bar a hason its inner face one substantially 9 straight but'inclined guideway anda second guideway which at its rear end branches and bends away from thefirst'named guideway and extends therefrom forward in a directionapproximately parallel with said first named guideway, and a lug whichproject-s laterally from the cam. plate and engages said guideway.

In testimony whereof, I hereunto affix my signaturein the presence oftwo witnesses,

RUSSELL B. TEWKSBURY.

v Witnesses E. L. THURs'roN, A. J. HUDSON.

five cents each, byaddress'ing the Commissioner of Patents, Washington,.D. 0.

